KFW70? New construction, which heating, air-to-water heat pump, underfloor heating, KfW85 instead of KfW70

... why I decided on the condensing boiler with solar @€uro, as mentioned at the beginning, I am not a fan of an air-to-water heat pump. I certainly don't want an unsightly and even noise-producing outdoor unit in the garden... The air-to-water heat pump is just as crazy as the heating support from the solar system. If I need warm air in winter for the air-to-water heat pump, it is not available. Then I have to operate the heating using the heating element. In that case, I might as well use a tankless water heater.

Gas condensing technology is the tried-and-true technology; there is more experience in this sector. Or can one say at this point in time that the air-to-water heat pump lasts longer than a condensing unit? I don’t think so.

Sizing the system with 19KW was the suggestion from the heating engineer, with the reasoning that the boiler heats up faster...

@Nutshell - where exactly did the Viessmann boiler place first (which test?)

How do the other manufacturers perform?

Regards

So a 19kw boiler... holy cow
It can't be cheaper than a smaller one, I mean... a V12 is also more expensive than a 4-cylinder engine!

... Designing the system with 19KW was the suggestion from the heating engineer, with the reasoning that the boiler heats up faster...

If you fall for salespeople whose primary interest is their own profit, you end up with such overall costly "suggestions"

best regards

Hi What exactly should heat up faster there? Kfw 70 means in my opinion underfloor heating, low flow temperature, and gradual but sustained warmth. That doesn't require much power. Rapid heating of domestic hot water is not an issue with an appropriate water storage tank. Only with a high number of people and a too small storage tank would that be a consideration, but that should rather lead to a larger storage tank than to an oversized heating system for the rare eventuality. Better to have the exact heating demand calculation shown and then choose the dimension accordingly. bye Explosiv who also decided against a heat pump and for gas condensing boiler with solar for domestic hot water